Nippon Steel Corporation

Yuziro Ueda

Toru Yoshida

Michiyasu Honda

Michitaka Kanemoto

Shin-ichi Sanuki

Katsuyuki Isogami

Tomoaki Kume

Kosaburo Ikenouchi

An oxygen blow steelmaking furnace comprises a device for supplying materials for blowing into the furnace, a plurality of sensing devices, and a computer control device. The supplying device supplies into the furnace oxygen and fluxes from above and, as occasion demands, at least one of oxygen, carbon dioxide and inert gas from below. The sensing devices individually respond to different properties that represent the blowing condition. The computer control device sets a program for the blow based on the charging and blowing-out conditions, responds to the sensing devices, and outputs the operating instructions to the supplying device. The computer control device includes a device that determines the oxygen content is slag based on the aforementioned properties and the amount of operational correction according to the deviation between the computed and targeted oxygen contents, and a device that estimates, immediately before the completion of the blow, the temperature and carbon content of the hot metal at the end point based on the aforesaid properties and oxygen content in slag and determines the amount of operational correction according to the difference between the estimated and targeted hot-metal temperatures and carbon contents.

Oxygen-blown steelmaking furnace

A method for recovering unburnt exhaust gases in an oxygen converter, characterized by the control of an exhaust gas damper by a control signal obtained by signal-processing, in accordance with the set functional formulae, an exhaust gas damper control signal obtained from a pressure differential between throat pressure and atmospheric pressure, and an exhaust gas damper prediction control signal obtained by continuously detecting the quantity of oxygen fed, the quantity of secondary raw material charged, the composition of exhaust gases and the flow rate of exhaust gases to calculate the quantity of furnace generated gases and the quantity of combustion exhaust gases at throat.

Method for controlling exhaust gases in oxygen blown converter

A method for recovering unburnt exhaust gases in an oxygen converter, is described, which involves the control of an exhaust gas damper by means of a control signal obtained by signal-processing, in accordance with set functional formulae, an exhaust gas damper control signal obtained from the pressure differential between the converter throat pressure and atmospheric pressure, and an exhaust gas damper prediction control signal obtained by continuously detecting the quantities of oxygen fed and of secondary raw material charged, as well as the composition of the exhaust gases and the flow rate of exhaust gases. With this signal processing the quantity of furnace generated gases and the quantity of combustion exhaust gases at the converter throat are calculated and the degree of optimum aperture of the converter damper is controlled.

A method of controlling the temperature of molten steel and the carbon content in an oxygen converter comprising the steps of, making measurements by the use of a detecting probe at the suitable time in the midst of the blowing; measuring the actual value at that time as the starting point for the thereafter operation of prediction; using the amount of slag accumulated oxygen as a principal parameter for operation of the prediction, and combining the third feature stated above with the second feature stated above for obtaining the predicted value with higher accuracy.

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Sakai, Japan

Yuziro Ueda